Valve bridge having a centrally positioned hydraulic lash adjuster

Abstract

A valve bridge configured to engage an engine valve is disclosed. The valve bridge includes a bridge cavity formed within a center portion of the valve bridge and including a bottom surface. A hydraulic lash adjuster is slidably disposed within the bridge cavity.

1. A valve bridge comprising:
 a bridge cavity formed within a center portion of the valve bridge, the bridge cavity including a closed bore extending into the center portion of the valve bridge, the closed bore including a continuous fixed bottom surface that fully seals a bottom portion of the bridge cavity; 
 a hydraulic lash adjuster slidably disposed within the bridge cavity, and wherein the valve bridge is configured to engage at least two engine valves. 
 
     
     
       2. The valve bridge of  claim 1 , wherein the hydraulic lash adjuster includes a plunger slidably disposed within the bridge cavity. 
     
     
       3. The valve bridge of  claim 2 , wherein the plunger includes a reservoir chamber configured to receive a fluid, the reservoir chamber including a first end and a second end. 
     
     
       4. The valve bridge of  claim 3 , further including a check valve proximate the second end of the reservoir chamber. 
     
     
       5. The valve bridge of  claim 3 , further including a spring proximate the second end of the reservoir chamber and configured to bias the plunger and the bottom surface of the bridge cavity. 
     
     
       6. The valve bridge of  claim 4 , further including a hydraulic chamber disposed between the check valve and the bottom surface of the bridge cavity and configured to receive the fluid through the check valve. 
     
     
       7. A compression braking system configured to actuate at least two engine valves, comprising:
 a valve bridge configured to engage the at least two engine valves and including a bridge cavity formed within a center portion of the valve bridge, the bridge cavity including a bottom surface; 
 a hydraulic lash adjuster slidably disposed within the bridge cavity; 
 a rocker arm including a valve actuation side configured to engage the hydraulic lash adjuster and a passage configured to direct a fluid to the hydraulic lash adjuster; 
 a driving output configured to actuate the rocker arm; and 
 wherein the compression braking system is configured such that fluid is substantially sealed within the bridge cavity whenever that the rocker arm is moving the hydraulic lash adjuster and the valve bridge. 
 
     
     
       8. The compression braking system of  claim 7 , wherein the hydraulic lash adjuster includes a plunger slidably disposed within the bridge cavity. 
     
     
       9. The compression braking system of  claim 8 , wherein the plunger includes a reservoir chamber configured to receive the fluid, the reservoir chamber including a first end and a second end. 
     
     
       10. The compression braking system of  claim 9 , further including a check valve proximate the second end of the reservoir chamber. 
     
     
       11. The compression braking system of  claim 9 , further including a spring proximate the second end of the reservoir chamber and configured to bias the plunger and the bottom surface of the bridge cavity. 
     
     
       12. The compression braking system of  claim 10 , further including a hydraulic chamber disposed between the check valve and the bottom surface of the bridge cavity and configured to receive the fluid through the check valve. 
     
     
       13. The compression braking system of  claim 9 , further including a hollow member associated with the valve actuation side of the rocker arm, the hollow member configured to be in fluid communication with the plunger. 
     
     
       14. The compression braking system of  claim 13 , wherein the hollow member includes a channel configured to direct the fluid from the passage of the rocker arm to the reservoir chamber. 
     
     
       15. The compression braking system of  claim 13 , further including a button member associated with the hollow member and configured to engage the first end of the reservoir chamber. 
     
     
       16. An engine assembly including at least two engine valves, the engine assembly comprising:
 a compression braking system configured to actuate the at least two engine valves including:
 a valve bridge having at least two fixed recesses that engage stems of the at least two engine valves in a manner preventing substantial sliding of the valves relative to the valve bridge whenever the compression braking system is operating to actuate the at least two valves, and wherein the valve bridge includes a bridge cavity formed within a center portion of the valve bridge, the bridge cavity including a closed bore extending into the center portion of the valve bridge, the closed bore including a continuous fixed bottom surface that fully seals a bottom portion of the bridge cavity; 
 a hydraulic lash adjuster slidably disposed within the bridge cavity; a rocker arm including a valve actuation side configured to engage the hydraulic lash adjuster and a passage configured to direct a fluid to the hydraulic lash adjuster; and 
 a driving output configured to actuate the rocker arm. 
 
 
     
     
       17. The engine assembly of  claim 16 , wherein the hydraulic lash adjuster includes a plunger slidably disposed within the bridge cavity, the plunger including a reservoir chamber configured to receive the fluid. 
     
     
       18. The engine assembly of  claim 17 , further including a check valve proximate a second end of the reservoir chamber and a hydraulic chamber disposed between the check valve and the bottom surface of the bridge cavity, the hydraulic chamber configured to receive the fluid through the check valve. 
     
     
       19. The engine assembly of  claim 18 , further including a hollow member associated with the valve actuation side of the rocker arm, the hollow member including a channel configured to be in fluid communication with the reservoir chamber of the plunger. 
     
     
       20. The engine assembly of  claim 19 , further including a button member associated with the hollow member and configured to engage the first end of the reservoir chamber. 
     
     
       21. An engine assembly including at least two engine valves, the engine assembly comprising:
 a compression braking system configured to actuate the at least two engine valves including:
 a valve bridge configured to engage the at least two engine valves and including a bridge cavity formed within a center portion of the valve bridge, the bridge cavity including a bottom surface; 
 a hydraulic lash adjuster slidably disposed within the bridge cavity; 
 a rocker arm including a valve actuation side configured to engage the hydraulic lash adjuster and a passage configured to direct a fluid to the hydraulic lash adjuster; and 
 
 a driving output configured to actuate the rocker arm, the driving output including a hydraulically actuated slave piston that is separate from the hydraulic lash adjuster and configured to actuate the rocker arm to drive the lash adjuster, the valve bridge, and the at least two engine valves to provide compression braking.